Qin Yanchuan, the sole successor of Xuanqi Mountain, is ordered by his master to go down the mountain, wanting only to cancel all three engagement letters. Due to an accident three years ago, Jiang Yutang has lost all sensation in her legs, and the medicine bottle left at the scene unexpectedly bears the dark patterns of Xuanqi Mountain. As the investigation deepens, the Pei family's banned drugs, the truth behind the disappearance of Jiang Yutang's father Jiang Cheng'an, and the old grievances of the sect surface one after another. While canceling engagements and saving people to investigate cases, Qin Yanchuan and Jiang Yutang go from mutual probing and bickering to breaking through dangers together time and again and trusting each other. Until all the old engagements are canceled, he discovers that the person he truly wants to keep is never the one chosen for him by the engagement letters.